Reactive byproduct treatment in gas generators

Abstract

The disclosure provides devices, methods, and systems for treating reactive metals and other reactive species produced during operation of thermal solid-state gas generators. Thermal energy, which may be derived from the gas generation process, physical contact with the evolved gases, or a dedicated or shared heat source, is used to release a gaseous species that neutralizes the reactive species. In some embodiments, the neutralization reaction causes the release of additional product gas(es).

The invention claimed is: 
     
       1. A gas generator device, comprising:
 a heat-generating composition, configured to undergo a reaction that releases heat when ignited; 
 a product gas-generating composition, configured to thermally decompose to release a product gas and a reactive species upon receiving at least a portion of the heat released by reaction of the heat-generating composition; and 
 a neutralizing gas-generating composition, 
 wherein the gas generator device is configured to heat the neutralizing gas-generating composition and thereby cause the neutralizing gas-generating composition to undergo a phase change or thermal decomposition to release a neutralizing gas, and 
 wherein the gas generator device is further configured to cause at least a portion of the reactive species and at least a portion of the neutralizing gas to contact and chemically react with each other to form a less reactive species. 
 
     
     
       2. The gas generator device of  claim 1 , further comprising:
 a first compartment, containing the heat-generating composition; 
 a second compartment, containing the product gas-generating composition; and 
 a first separator, positioned between and separating the first and second compartments, 
 wherein the gas generator device is configured such that, when the reaction of the heat-generating composition is initiated by ignition of the heat-generating composition, at least a portion of the heat released by the reaction is transferred from the first compartment to the second compartment via the first separator at a first heat transfer rate. 
 
     
     
       3. The gas generator device of  claim 2 , further comprising:
 a third compartment, containing the neutralizing gas-generating composition; and 
 a second separator, positioned between and separating the second and third compartments, 
 wherein the gas generator device is further configured such that at least a portion of the heat transferred from the first compartment to the second compartment via the first separator is subsequently transferred from the second compartment to the third compartment via the second separator at a second heat transfer rate. 
 
     
     
       4. The gas generator device of  claim 1 , wherein at least a portion of the neutralizing gas-generating composition is disposed within an outlet path of the product gas. 
     
     
       5. The gas generator device of  claim 1 , wherein the heat-generating composition and the product gas-generating composition are provided in a reactive stack, wherein the reactive stack is disposed within an interior volume of the gas generator device, and wherein at least a portion of the neutralizing gas-generating composition is disposed within the interior volume. 
     
     
       6. The gas generator device of  claim 5 , wherein the neutralizing gas-generating composition at least partially circumferentially surrounds the reactive stack within the interior volume. 
     
     
       7. The gas generator device of  claim 5 , wherein the neutralizing gas-generating composition is provided at a base of or below the reactive stack. 
     
     
       8. The gas generator device of  claim 1 , wherein the heat-generating composition comprises a thermite composition, the thermite composition comprising a mixture of a metal fuel and a metal oxide oxidizer that undergoes an exothermic reduction-oxidation reaction when ignited by heat. 
     
     
       9. The gas generator device of  claim 1 , wherein the product gas-generating composition comprises a metal hydride. 
     
     
       10. The gas generator device of  claim 1 , wherein the product gas is hydrogen gas. 
     
     
       11. The gas generator device of  claim 1 , wherein the reactive species comprises at least one of an alkali metal in elemental form and an alkali metal hydride. 
     
     
       12. The gas generator device of  claim 1 , wherein the neutralizing gas-generating composition comprises at least one of a hydrated metal salt, a halogen in elemental form, a metal halide, an ammonium salt, a compound containing an ammonia-bearing complex ion, or an alcohol. 
     
     
       13. The gas generator device of  claim 1 , wherein the neutralizing gas comprises at least one of water vapor and a halogen. 
     
     
       14. The gas generator device of  claim 1 , configured to heat the neutralizing gas-generating composition by at least one of (i) physical contact with the product gas, (ii) residual or waste heat from reaction of the heat-generating composition, (iii) residual or waste heat from thermal decomposition of the product gas-generating composition, wherein the thermal decomposition of the product gas-generating composition is exothermic, and (iv) a separate portion of heat-generating composition. 
     
     
       15. The gas generator device of  claim 1 , further comprising an igniter configured to ignite the heat-generating composition. 
     
     
       16. A method, comprising:
 (a) initiating a reaction of a heat-generating composition to release thermal energy; 
 (b) thermally decomposing, by at least a portion of the thermal energy released in step (a), at least a portion of a product gas-generating composition to release a product gas and a reactive species; 
 (c) heating a neutralizing gas-generating composition to release a neutralizing gas; and 
 (d) contacting at least a portion of the reactive species with at least a portion of the neutralizing gas to cause a chemical reaction that forms a less reactive species. 
 
     
     
       17. The method of  claim 16 , wherein at least a portion of the neutralizing gas-generating composition is disposed within an outlet path of the product gas. 
     
     
       18. The method of  claim 16 , wherein the heat-generating composition and the product gas-generating composition are provided in a reactive stack, wherein the reactive stack is disposed within an enclosed volume, and wherein at least a portion of the neutralizing gas-generating composition is disposed within the enclosed volume. 
     
     
       19. The method of  claim 18 , wherein the neutralizing gas-generating composition at least partially circumferentially surrounds the reactive stack within the enclosed volume. 
     
     
       20. The method of  claim 18 , wherein the neutralizing gas-generating composition is provided at a base of or below the reactive stack. 
     
     
       21. The method of  claim 16 , wherein the heat-generating composition comprises a thermite composition, the thermite composition comprising a mixture of a metal fuel and a metal oxide oxidizer that undergoes an exothermic reduction-oxidation reaction when ignited by heat. 
     
     
       22. The method of  claim 16 , wherein the product gas-generating composition comprises a metal hydride. 
     
     
       23. The method of  claim 16 , wherein the product gas is hydrogen gas. 
     
     
       24. The method of  claim 16 , wherein the reactive species comprises at least one of an alkali metal in elemental form and an alkali metal hydride. 
     
     
       25. The method of  claim 16 , wherein the neutralizing gas-generating composition comprises at least one of a hydrated metal salt, a halogen in elemental form, a metal halide, an ammonium salt, or a compound containing an ammonia-bearing complex ion, or an alcohol. 
     
     
       26. The method of  claim 16 , wherein the neutralizing gas comprises at least one of water vapor and a halogen. 
     
     
       27. The method of  claim 16 , wherein step (c) is carried out by at least one of (i) physical contact with the product gas, (ii) residual or waste heat from reaction of the heat-generating composition, (iii) residual or waste heat from thermal decomposition of the product gas-generating composition, wherein the thermal decomposition of the product gas-generating composition is exothermic, and (iv) a separate portion of heat-generating composition. 
     
     
       28. An inflatable device, comprising:
 an inflatable article; and 
 the gas generator device of  claim 1 , interconnected to and configured to inflate the inflatable article with the product gas. 
 
     
     
       29. A gas generator device, comprising:
 a heat-generating composition, configured to undergo a reaction that releases heat when ignited; 
 a product gas-generating composition, configured to thermally decompose to release a product gas and a reactive species upon receiving at least a portion of the heat released by reaction of the heat-generating composition; and 
 a neutralizing gas-generating composition contained in a sealed environment, 
 wherein the gas generator device is configured to cause the sealed environment to open to cause the release of a neutralizing gas, and 
 wherein the gas generator device is further configured to cause at least a portion of the reactive species and at least a portion of the neutralizing gas to contact and chemically react with each other to form a less reactive species. 
 
     
     
       30. The gas generator device of  claim 29 , further comprising:
 a first compartment, containing the heat-generating composition; 
 a second compartment, containing the product gas-generating composition; and 
 a first separator, positioned between and separating the first and second compartments, 
 wherein the gas generator device is configured such that, when the reaction of the heat-generating composition is initiated by ignition of the heat-generating composition, at least a portion of the heat released by the reaction is transferred from the first compartment to the second compartment via the first separator at a first heat transfer rate. 
 
     
     
       31. The gas generator device of  claim 29 , wherein the sealed environment comprises a sealed packet surrounding the neutralizing gas-generating composition and the opening of the sealed environment comprises melting or thermal degradation of a material of the sealed packet. 
     
     
       32. The gas generator device of  claim 29 , wherein the heat-generating composition comprises a thermite composition, the thermite composition comprising a mixture of a metal fuel and a metal oxide oxidizer that undergoes an exothermic reduction-oxidation reaction when ignited by heat. 
     
     
       33. The gas generator device of  claim 29 , wherein the product gas-generating composition comprises a metal hydride. 
     
     
       34. The gas generator device of  claim 29 , wherein the product gas is hydrogen gas. 
     
     
       35. The gas generator device of  claim 29 , wherein the reactive species comprises at least one of an alkali metal in elemental form and an alkali metal hydride. 
     
     
       36. The gas generator device of  claim 29 , wherein the neutralizing gas comprises at least one of water vapor and a halogen. 
     
     
       37. The gas generator device of  claim 29 , further comprising an igniter configured to ignite the heat-generating composition. 
     
     
       38. A method, comprising:
 (a) initiating a reaction of a heat-generating composition to release thermal energy; 
 (b) thermally decomposing, by at least a portion of the thermal energy released in step (a), at least a portion of a product gas-generating composition to release a product gas and a reactive species; 
 (c) causing a sealed reservoir containing a neutralizing gas to open to release the neutralizing gas; and 
 (d) contacting at least a portion of the reactive species with at least a portion of the neutralizing gas to cause a chemical reaction that forms a less reactive species. 
 
     
     
       39. The method of  claim 38 , wherein the heat-generating composition and the product gas-generating composition are provided in a reactive stack, wherein the reactive stack is disposed within an enclosed volume, and wherein at least a portion of the sealed reservoir is disposed within the enclosed volume. 
     
     
       40. The method of  claim 39 , wherein the sealed reservoir at least partially circumferentially surrounds the reactive stack within the enclosed volume. 
     
     
       41. The method of  claim 39 , wherein the sealed reservoir is provided at a base of or below the reactive stack. 
     
     
       42. The method of  claim 38 , wherein the heat-generating composition comprises a thermite composition, the thermite composition comprising a mixture of a metal fuel and a metal oxide oxidizer that undergoes an exothermic reduction-oxidation reaction when ignited by heat. 
     
     
       43. The method of  claim 38 , wherein the product gas-generating composition comprises a metal hydride. 
     
     
       44. The method of  claim 38 , wherein the product gas is hydrogen gas. 
     
     
       45. The method of  claim 38 , wherein the reactive species comprises at least one of an alkali metal in elemental form and an alkali metal hydride. 
     
     
       46. The method of  claim 38 , wherein the neutralizing gas comprises at least one of iodine, bromine, an alcohol, and water. 
     
     
       47. An inflatable device, comprising:
 an inflatable article; and 
 the gas generator device of  claim 29 , interconnected to and configured to inflate the inflatable article with the product gas.